Small sight—Big might: Economic impact of bird tourism shows opportunities for rural communities and biodiversity conservation

following AVSP methodology [21]. We used R for data management and survey data analysis to first subset the data into visitors who reported to have been bird watching on their Alaska trip (S1 Code). We scaled expenditures to the population level by applying market shares according to the main purpose of the trip including visiting for pleasure/vacation, visiting friends, and business travel [21]. Specifically, we calculated the scale factors to equal 438 for vacationers, 267 for visiting friends, and 278 for business travellers (S1 Code). AVSP’s expenditure data includes spending by category and by location which we used to attribute expenditures to economic sectors and regions (S2 Table). This attribution is espe- cially important for tourism analysis as the sector is comprised of many sub-sectors including lodging; tours, activities, and entertainment; gifts, souvenirs, and clothing; food and beverages; and rental cars, fuel, and other transportation [21]. AVSP includes expenditure category “other”, which we proportionally re-allocated across the remaining five spending categories (S1 and S2 Tables). For the purpose of regional economic analysis, we aggregated AVSP expenditures into regional economies consisting of groups of Alaska’s organized boroughs and census areas (Fig 1). These regions roughly encompassed Alaska’s five Bird Conservation Regions as defined by the North American Bird Conservation Initiative and described in more detail in the following section [15] (Fig 1 and S1 Table). The aggregation allowed for a region-specific analysis of eco-

nomic impacts related to each Bird Conservation Region. To analyze the potential discrepancy between where expenditures occur and where birds are being observed and to validate the AVSP data, we used eBird data to calculate the average group size per reporting bird observer across submitted observations per region [16]. If observ- ers did not report group size, we set group size equal to one. We then summed the average group sizes for all reporting bird observers to estimate the number of observers for each of Alas- ka’s five Bird Conservation Regions (S1 Code) (Cornell Lab of Ornithology, 2021). Input-output analysis We used input-output analysis to investigate the economic impacts of bird tourism [33,34], using IMPLAN software, a widely used input-output model that was developed by the U.S. Forest Service [35]. Our analysis measured the net changes to a regional economy that are attributable to related bird-watching visitor spending. The five regional economic models followed roughly the outlined Alaska Bird Conservation Regions and each consisted of a subset of Alaska’s census areas and boroughs (Fig 1) [15] (S2 Table). IMPLAN simulates interactions of 528 unique economic sectors, using data collected by federal and state government agencies. For each AVSP expenditure category we assigned the most closely related IMPLAN sector among IMPLAN’s industry and commodity accounts and then applied the estimated total expenditures to those accounts (S3 Table). For each region, we paid particular attention to IMPLAN’s industry and commodity

accounts that best described the expenditure category by region. For example, for lodging in the Arctic Plains and Western Alaska regions, we assigned lodging expenditures as an industry change equally proportioned among the hotels/motels and other accommodations accounts, whereas for the Interior and Rainforest regions we used a ¾ and ¼ allocation respectively (S3 Table) [33]. This approach acknowledged the relatively small number of hotels in the Arctic Plains and Western Alaska regions compared to other accommodations such as e.g. bed and breakfasts [36]. Similarly, we modelled expenditures on tours as a commodity change and assigned it to the scenic and sightseeing sector in the Arctic Plains and Western Alaska regions while also using the museums and other amusement accounts for the Interior region, consistent with a more diverse supply of entertainment services in the Interior region (S3 Table) [36]. PLOS ONE Economic impact of bird tourism in Alaska PLOS ONE | https://doi.org/10.1371/journal.pone.0268594 July 6, 2022 7 / 18